Humidity Sensor Calibration - Microchip Technology Humidity Sensor PICtail User Manual

3.4

HUMIDITY SENSOR CALIBRATION

If desired, the capacitive humidity sensor used on this board can be calibrated. Manu-
facturing tolerances, aging and changes in circuit operating conditions (i.e., supply
voltage and temperature) may cause errors larger than desired. Many reputable
companies provide humidity calibration equipment and/or services.
There are two common approaches to calibrating these sensors:
1. Put sensor in an atmosphere with well controlled RH.
2. Use another, more accurate sensor to measure the RH.
In both cases, there are two areas of concern. First, the RH can change rapidly across
time and position, making an accurate calibration difficult to do. Second, it takes time
for humidity sensors to settle to an accurate value. Some can take many minutes to
settle properly.
© 2005 Microchip Technology Inc.
Operation
DS51594A-page 15